Figure 1-9 Typical Component Locations; System Components - Carrier Transport Air Conditioning Installation Procedures Manual

1.4 SYSTEM COMPONENTS

1. Thermostat - A thermostat is a temperature
sensitive device, which when activated, signals the
electro-magnetic clutch to engage.
2. Electro-Magnetic Clutch - The electro-magnetic
clutch controls the operation of the compressor. When
engaged, the compressor circulates refrigerant and
provides cooling (See Figure 1-9).
3. Compressor - The compressor is a belt driven,
high-pressure pump, which circulates the refrigerant
through the evaporator
Figure 1-9). The operation of the compressor is
controlled by the electro-magnetic clutch, which in turn
is controlled by the thermostat.
4. Condenser - The condenser is normally located in
the skirt or on the roof of the bus (vehicle), (See
Figure 1-9). Its primary function is to reject heat, which
was transferred to the refrigerant by the evaporator from
the passenger compartment of the bus (vehicle).
5. Filter/Dryer & Receiver/Drier -- The filter/dryer and
receiver/drier removes moisture and particulate matter
1
1. Compressor
2. Discharge Line (hot gas)
3. Condenser
4. Liquid Line
and condenser (See
2

Figure 1-9 Typical Component Locations

1--5
from the refrigerant. The receiver/drier also stores liquid
refrigerant (See Figure 1-9).
6. Expansion Valve/Block Valve - Meters the
refrigerant flow into the evaporator coil.
7. Evaporator - The evaporator is located in the interior
of the bus (vehicle) (See Figure 1-9). Its primary
function is to transfer heat contained in the passenger
compartment air, into the refrigerant, which is circulated
by the compressor, through the evaporator coil. During
this process the air is also filtered and dehumidified
8. Refrigerant - A refrigerant is any material that
possesses high heat transfer capabilities. Its primary
function is to act as the medium for heat transfer, which
facilitates the movement of heat from the passenger
compartment to the outside air. Refrigerant under
varying pressures exists in different states, and
performs different heat transfer functions. Under low
pressure, refrigerant exists as a gas that can absorb
heat. under high pressure, refrigerant exists as a liquid
that can reject heat. The heat transfer properties
exhibited when refrigerant changes state is the
foundation of the refrigerant cycle.
Cool Air Out
7
Ambient Air In
3
5. Filter--Drier or Receiver--Drier
6. Evaporator
7. Suction Line
6
4
5
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